The goal of the proposed work is to employ a sequence of research steps leading to a model for the use of non-destructive gill biopsies of fish to monitor marine contamination at Superfund sites and identify changes in the health status of this resource. The results would provide a significant understanding of relationships between environmental contamination histology and a group of discerning biomarkers relating to fish health. The specific aims are: 1) collect fish and marine sediments from contaminated locations and uncontaminated reference areas in Puget Sound, WA (English sole) and the San Francisco Bay Area (surf perch), areas that have a wide spread of contaminant burdens and biological impacts; 2) measure the aryl hydrogen (Ah)-inducing contamination in marine sediments using the P450 Reporter Gene System (RGS) assay, perform histological examination of liver, kidney and gill tissues and analyze DNA from each tissue using gas chromatography-mass spectrometry (GC0MS) and Fourier transform-infrared (FT-IR) spectroscopy. Complementary cytochrome P450 1A (CYP1A) and nuclear factor kappa B (NfkappaB) models would be employed in conjunction with the DNA models; 3) determine the association of the histology of biomarker data with the level of sediment contamination and P4501A induction. Then determine whether the biological indicators applied to ecologically non-destructive gill tissues and P4501A induction. Then determine whether the biological indicators applied to ecologically non-destructive gill tissues could be used alone for the assessment of fish health at Superfund sites and 4) determine if the association between sediment contamination, histology and the biomarkers are similar between English sole and serf perch to see if the use of the biological indicators is independent of fish species. Alternative, if species differences are a factor, establish a health-related model that takes this into account.